Buffer Device Segregating DMA Access for Security and Power
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Solution Overview
Problem
Direct-memory access (DMA) to main system memory poses security threats due to potential memory area or buffer overflows and increases power consumption by keeping memory active in low-power modes.
Innovation Solution
A buffer device with a buffer memory module and controller, connected between peripheral devices and a processor, that segregates memory access, blocks unauthorized access, and manages memory segment sizes and access permissions to prevent security threats and reduce power consumption by operating in a different power domain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If DMA is used to allow peripheral devices to directly access main system memory, then data transfer efficiency is improved, but security risks increase due to potential memory area overflow or buffer overflow that can inject executable code
Solution Approach 1:
The patent introduces a buffer device as an intermediary component between peripheral devices and main system memory. This buffer device includes a buffer memory module with multiple memory segments that are isolated from the main system memory, preventing direct DMA access to main memory while still enabling efficient data transfer through the buffer. The buffer controller manages data flow between peripherals and buffer memory, eliminating security risks associated with direct DMA access.
Solution Approach 2:
The buffer memory module is divided into multiple independent memory segments, each potentially dedicated to specific peripheral devices or data types. This segmentation isolates data from different sources, preventing buffer overflow from one peripheral from affecting other memory areas or the main system memory, thus enhancing security while maintaining efficient data transfer.
2Adaptability or versatility
If main system memory remains active during low-power modes to support DMA operations, then data transfer capability is maintained, but power consumption increases
Solution Approach 1:
The buffer device serves as an autonomous intermediary that can operate independently from the main system memory power state. The buffer memory module and buffer controller form a self-contained data transfer system that maintains DMA functionality even when main system memory is in low-power mode, allowing the processor and main memory to enter low-power states while data transfer operations continue through the buffered memory.
3Device complexity
If direct DMA access to main system memory is allowed, then device complexity is reduced by eliminating intermediate buffering, but security threats increase due to unauthorized code injection
Solution Approach 1:
The buffer device is introduced as a necessary intermediary between peripheral devices and main system memory. While this adds a component to the architecture, it significantly reduces overall system complexity by providing a dedicated, isolated buffering layer that handles all DMA operations. This prevents the need for complex security checks and validation logic in the main memory controller, as the buffer inherently protects against unauthorized access and code injection.
Data Source
AI summary
Embodiments of a buffer device, an electronic system, and a method for operating a buffer device are disclosed. In an embodiment, a buffer device includes buffer bus connections, a peripheral bus interface connectable to a peripheral bus, a buffer memory module, and a buffer memory controller connected between the buffer bus connections, the peripheral bus interface, and the buffer memory module. Each of the buffer bus connections is connectable to a respective peripheral device. The buffer memory module comprises memory segments corresponding to the peripheral devices. The buffer memory controller is configured to control data communications between the buffer bus connections, the peripheral bus interface, and the buffer memory module.